"question of naming the units for these fields and related quantities, among them the integral of magnetic flux density. In 1935, TC 1 recommended names for several electrical units, including the weber for the practical unit of magnetic flux (and the maxwell for the CGS unit). It was decided to extend the existing series of practical units into a complete comprehensive system of physical units, the recommendation being adopted in 1935 ""that the system with four fundamental units proposed by Professor Giorgi be adopted subject to the fourth fundamental unit being eventually selected"". This system was given the designation of"
"and external fields is not part of this internal energy. The unit for magnetic moment in terms of the International System of Units (SI) base units is A⋅m, where A is the ampere (the SI unit of current) and m is the meter (the SI unit of distance). This has equivalents in other units used in SI including: where N is the newton (the SI unit of force), T is the tesla (the SI unit of magnetic flux density), and J is the joule (the SI unit of energy). In the CGS system, there are several different sets of electromagnetism"
"symbol is uppercase (""G""), but when the unit is spelled out, it should be written in lowercase (""gauss""), unless it begins a sentence. Gauss (unit) The gauss, abbreviated as G or Gs, is the cgs unit of measurement of magnetic flux density (or ""magnetic induction"") (B). It is named after German mathematician and physicist Carl Friedrich Gauss. One gauss is defined as one maxwell per square centimeter. The cgs system has been superseded by the International System of Units (SI), which uses the tesla (symbol T) as the unit of magnetic flux density. One gauss equals 1 tesla (100 μT),"
"Magnetic complex reluctance Magnetic complex reluctance (SI Unit: H) is a measurement of a passive magnetic circuit (or element within that circuit) dependent on sinusoidal magnetomotive force (SI Unit: At·Wb) and sinusoidal magnetic flux (SI Unit: T·m), and this is determined by deriving the ratio of their complex ""effective"" amplitudes.[Ref. 1-3] As seen above, magnetic complex reluctance is a phasor represented as ""uppercase Z mu"" where: The ""lossless"" magnetic reluctance, ""lowercase z mu"", is equal to the absolute value (modulus) of the magnetic complex reluctance. The argument distinguishing the ""lossy"" magnetic complex reluctance from the ""lossless"" magnetic reluctance is equal"
"'magnetic field' is used to describe as well as or in place of . There are many alternative names for both (see sidebar). In SI units, is measured in teslas (symbol: T) and correspondingly (magnetic flux) is measured in webers (symbol: Wb) so that a flux density of 1 Wb/m is 1 tesla. The SI unit of tesla is equivalent to (newton·second)/(coulomb·metre). In Gaussian-cgs units, is measured in gauss (symbol: G). (The conversion is 1 T = 10000 G.) One nanotesla is equivalent to 1 gamma (symbol: γ). The -field is measured in amperes per metre (A/m) in SI units,"
"Gauss (unit) The gauss, abbreviated as G or Gs, is the cgs unit of measurement of magnetic flux density (or ""magnetic induction"") (B). It is named after German mathematician and physicist Carl Friedrich Gauss. One gauss is defined as one maxwell per square centimeter. The cgs system has been superseded by the International System of Units (SI), which uses the tesla (symbol T) as the unit of magnetic flux density. One gauss equals 1 tesla (100 μT), so 1 tesla = 10,000 gauss. As with all units whose names are derived from a person's name, the first letter of its"
"Maxwell (unit) The maxwell (symbol: Mx) is the CGS (centimetre-gram-second) unit of magnetic flux (). The unit name honours James Clerk Maxwell, who presented a unified theory of electromagnetism. The ""maxwell"" was recommended as a CGS unit at the International Electrical Congress held in 1900 at Paris. This practical unit was previously called a ""line"", reflecting Faraday's conception of the magnetic field as curved lines of magnetic force, which he designated as ""line of magnetic induction"". ""Kiloline"" (10 line) and ""megaline"" (10 line) were sometimes used because 1 line was very small relative to the phenomena that it was used"
"per coulomb (). Thus, the SI base units of electric flux are . Its dimensional formula is . Electric flux In electromagnetism, electric flux is the measure of the distribution of the electric field through a given surface, although an electric field in itself cannot flow. It is one way of describing the electric field strength at any distance from the charge causing the field. The electric field E can exert a force at any point in space. The electric field is proportional to the gradient of the voltage. The electric field is capable of moving charged particles. The ratio"
"units, of which the main ones are ESU, Gaussian, and EMU. Among these, there are two alternative (non-equivalent) units of magnetic dipole moment: where statA is statamperes, cm is centimeters, erg is ergs, and G is gauss. The ratio of these two non-equivalent CGS units (EMU/ESU) is equal to the speed of light in free space, expressed in cm⋅s. All formulae in this article are correct in SI units; they may need to be changed for use in other unit systems. For example, in SI units, a loop of current with current and area has magnetic moment (see below), but"
"in SI mks units and in Gaussian cgs units. Some confusion often arises because formula_4 is commonly used both for the magnetic diffusivity and for the resistivity of a plasma, with the relation in SI mks units being that formula_25. For formula_26, advection is relatively unimportant, and so the magnetic field will tend to relax towards a purely diffusive state, determined by the boundary conditions rather than the flow. For formula_27, diffusion is relatively unimportant on the length scale ""L"". Flux lines of the magnetic field are then advected with the fluid flow, until such time as gradients are concentrated"
"towards regions of higher flux so it is always an attractive force (pull). The reluctance of a uniform magnetic circuit can be calculated as: or where The inverse of reluctance is called ""permeance"". Its SI derived unit is the henry (the same as the unit of inductance, although the two concepts are distinct). Reluctance can also be applied to: Magnetic reluctance </math>, formula_1, formula_2 Magnetic reluctance, or magnetic resistance, is a concept used in the analysis of magnetic circuits. It is defined as the ratio of magnetomotive force (mmf) to magnetic flux. It represents the opposition to magnetic flux, and"
"case focus instead often rests on the influence of the magnetic field on the flow. formula_5 is widely used in plasma physics, where two types of SI units (Gaussian cgs and SI mks) are common, because the Gaussian cgs units often allow cleaner derivations from which the physical reasoning is more clear, so it is worthwhile to write down the derivation in both sets of units. In the theory of magnetohydrodynamics, the transport equation for magnetic field, formula_6, is in SI mks units and in Gaussian cgs units, for permeability of free space formula_9, speed of light formula_10, fluid velocity"
"to the natural number formula_7 raised to a power equal to: Where: The ""lossy"" magnetic complex reluctance represents a magnetic circuit element's resistance to not only magnetic flux but also to ""changes"" in magnetic flux. When applied to harmonic regimes, this formality is similar to Ohm's Law in ideal AC circuits. In magnetic circuits, magnetic complex reluctance is equal to: Where: Magnetic complex reluctance Magnetic complex reluctance (SI Unit: H) is a measurement of a passive magnetic circuit (or element within that circuit) dependent on sinusoidal magnetomotive force (SI Unit: At·Wb) and sinusoidal magnetic flux (SI Unit: T·m), and this"
"involve configurations more than a simple magnetic dipole; for example, quadrupole and sextupole magnets are used to focus particle beams. For most engineering applications, MKS (rationalized) or SI (Système International) units are commonly used. Two other sets of units, Gaussian and CGS-EMU, are the same for magnetic properties and are commonly used in physics. In all units, it is convenient to employ two types of magnetic field, B and H, as well as the magnetization M, defined as the magnetic moment per unit volume. Materials that are not permanent magnets usually satisfy the relation M = ""χH in SI, where"
"resp. a magnetic field, there is also the possibility of a magnetoelectric susceptibility formula_3 which describes a linear response of the electric polarization to a magnetic field, and vice versa: The tensor formula_6 must be the same in both equations. Here, P is the electric polarization, M the magnetization, E and H the electric and magnetic fields. The SI Unit of α is [s/m] which can be converted to the practical unit [V/(cm Oe)] by [s/m]=1.1 x10 ε [V/(cm Oe)]. For the CGS unit, [unitless] = 3 x 10 [s/m]/(4 x π) The first material where an intrinsic linear magnetoelectric"
"gamma (γ). The tesla is the SI unit of the magnetic field, B. The Earth's field ranges between approximately 25,000 and 65,000 nT (0.25–0.65 G). By comparison, a strong refrigerator magnet has a field of about . A map of intensity contours is called an ""isodynamic chart"". As the World Magnetic Model shows, the intensity tends to decrease from the poles to the equator. A minimum intensity occurs in the South Atlantic Anomaly over South America while there are maxima over northern Canada, Siberia, and the coast of Antarctica south of Australia. The inclination is given by an angle that"
"constant and standard unit for the magnetic moments of nuclear components. In SI units, the CODATA value of (). A magnetic moment is a vector quantity, and the direction of the proton's magnetic moment is defined by its spin. The torque on the proton resulting from an external magnetic field is towards aligning the proton's spin vector in the same direction as the magnetic field vector. The nuclear magneton is the spin magnetic moment of a Dirac particle, a charged, spin 1/2 elementary particle, with a proton's mass ""m"". In SI units, the nuclear magneton is where ""e"" is the"
"Magnetomotive force In physics, the magnetomotive force (mmf) is a quantity appearing in the equation for the magnetic flux in a magnetic circuit, often called Ohm's law for magnetic circuits. It is the property of certain substances or phenomena that give rise to magnetic fields: where ""Φ"" is the magnetic flux and ""R"" is the reluctance of the circuit. It can be seen that the magnetomotive force plays a role in this equation analogous to the voltage ""V"" in Ohm's law: ""V"" = ""IR,"" since it is the cause of magnetic flux in a magnetic circuit: The SI unit of"
"loops of current. For a sufficiently small loop of current, ""I"", and area, A, the magnetic dipole moment is: where the direction of m is normal to the area in a direction determined using the current and the right-hand rule. As such, the SI unit of magnetic dipole moment is ampere meter. More precisely, to account for solenoids with many turns the unit of magnetic dipole moment is Ampere-turn meter. In the Gilbert model, the magnetic dipole moment is due to two equal and opposite magnetic charges that are separated by a distance, ""d"". In this model, m is similar"
"the SI unit of magnetic flux density. An older name for the lumen second was the lumberg. The photometric unit lumerg, also proposed by the Committee on Colorimetry in 1937, correlates with the old CGS unit erg in the same way that the lumen second correlates with the radiometric unit joule, so that 10 lumerg = 1 lm⋅s. Lumen second In photometry, the lumen second (lm s or lm⋅s) is the SI derived unit of luminous energy. It is based on the lumen, the SI unit of luminous flux, and the second, the SI base unit of time. The lumen"
"this bound current; but to see how, it helps to introduce the concept of ""magnetization"" first. The ""magnetization"" vector field represents how strongly a region of material is magnetized. It is defined as the net magnetic dipole moment per unit volume of that region. The magnetization of a uniform magnet is therefore a material constant, equal to the magnetic moment of the magnet divided by its volume. Since the SI unit of magnetic moment is A⋅m, the SI unit of magnetization is ampere per meter, identical to that of the -field. The magnetization field of a region points in the"
"and often useful for switching between SI and cgs formulae: An electric flux (specifically, a flux of the electric displacement field D) has units of charge: statC in cgs and coulombs in SI. The conversion factor can be derived from Gauss's law: where Therefore, the conversion factor for flux is 4π different from the conversion factor for charge: The dimensionally consistent version is: Statcoulomb The statcoulomb (statC) or franklin (Fr) or electrostatic unit of charge (esu) is the physical unit for electrical charge used in the esu-cgs (centimetre–gram–second system of units) and Gaussian units. It is a derived unit given"
"electric field can also be interpreted as the electric force per unit charge. Flux can be thought of as the flow of the electric or magnetic field through a surface. Fields can be represented by flux lines. Flux is analogous to the flow of a fluid through a surface since the angle of the surface to the direction of flow determines how much fluid can flow through the surface. Gauss' law states that the flux through a closed surface is proportional to the amount of charge enclosed. The SI units of flux are newton meters-squared per coulomb (formula_6), or equivalently,"
"magnetic flux) — The weber is the magnetic flux that, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second. The weber is commonly expressed in a multitude of other units: where Wb = weber, <br>V = volt, <br>T = tesla, <br>J = joule, <br>m = metre, <br>s = second, <br>A = ampere, <br>H = henry, <br>Mx = maxwell. In 1861, the British Association for the Advancement of Science (known as ""The BA"") established a committee under William Thomson (later Lord"
"Radiant flux In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiant flux is the watt (W), that is the joule per second () in SI base units, while that of spectral flux in frequency is the watt per hertz () and that of spectral flux in wavelength is the watt per metre ()—commonly the watt"
"Heat flux Heat flux or thermal flux, sometimes also referred to as ""heat flux density"" or ""heat flow rate intensity"" is a flow of energy per unit of area per unit of time. In SI its units are watts per square metre (W⋅m). It has both a direction and a magnitude, and so it is a vector quantity. To define the heat flux at a certain point in space, one takes the limiting case where the size of the surface becomes infinitesimally small. Heat flux is often denoted formula_1, the subscript q specifying ""heat"" flux, as opposed to ""mass"" or"
"example in a Newton–Raphson iterative solution scheme that computes the changing saturation of a magnetic circuit. Permeability is the inductance per unit length. In SI units, permeability is measured in henries per metre (H·m = J/(A·m) = N·A). The auxiliary magnetic field H has dimensions current per unit length and is measured in units of amperes per metre (A·m). The product ""µ"" H thus has dimensions inductance times current per unit area (H·A/m). But inductance is magnetic flux per unit current, so the product has dimensions magnetic flux per unit area, that is, magnetic flux density. This is the magnetic"
"Mass flux In physics and engineering, mass flux is the rate of mass flow per unit area, perfectly overlapping with the momentum density, the momentum per unit volume. The common symbols are ""j"", ""J"", ""q"", ""Q"", ""φ"", or ""Φ"" (Greek lower or capital Phi), sometimes with subscript ""m"" to indicate mass is the flowing quantity. Its SI units are kg s m. Mass flux can also refer to an alternate form of flux in Fick's law that includes the molecular mass, or in Darcy's law that includes the mass density. Unfortunately, sometimes the defining equation for mass flux in this"
"example Monte Carlo integration. Heat flux Heat flux or thermal flux, sometimes also referred to as ""heat flux density"" or ""heat flow rate intensity"" is a flow of energy per unit of area per unit of time. In SI its units are watts per square metre (W⋅m). It has both a direction and a magnitude, and so it is a vector quantity. To define the heat flux at a certain point in space, one takes the limiting case where the size of the surface becomes infinitesimally small. Heat flux is often denoted formula_1, the subscript q specifying ""heat"" flux, as"
"Nuclear magneton The nuclear magneton (symbol ""μ""), is a physical constant of magnetic moment, defined in SI units by: and in Gaussian CGS units by: where: In SI units, its value is approximately: In Gaussian CGS units, its value can be given in convenient units as The nuclear magneton is the natural unit for expressing magnetic dipole moments of heavy particles such as nucleons and atomic nuclei. Due to the fact that neutrons and protons consist of quarks and thus are no real Dirac particles, their magnetic moment differ from formula_3: The magnetic dipole moment of the electron, which is"
"circuit. In the general case formula_29. When an energy loss is absent (formula_30), formula_31. The angle of the phase shift in a magnetic circuit formula_32. On a complex plane, the magnetic reactance appears as the side of the resistance triangle for circuit of an alternating current. Magnetic capacitivity (SI unit: H), denoted as formula_33, is an extensive property and is defined as: formula_34 Where: formula_35 is the magnetic permeability, formula_36 is the element cross-section, and formula_37 is the element length. For phasor analysis, the magnetic permeability and the magnetic capacitivity are complex values. Magnetic capacitivity is also equal to magnetic"
"as, ""The photon flux was 1500 μmol m s"". This unit was named after physicist Albert Einstein. Einstein (unit) The einstein is a unit defined as one mole () of photons. As such, photosynthetically active radiation (PAR) was formerly often reported in microeinsteins per second per square meter (μE m s). This usage is also not part of the International System of Units and when used this way it is redundant with the mole. Since the unit does not have a standard definition and is not part of the SI system, it is usually better to avoid its use. The"
"SI unit is kg/m (equal to g/L). The molar concentration formula_5 is defined as the amount of a constituent formula_6 (in moles) divided by the volume of the mixture formula_3: The SI unit is mol/m. However, more commonly the unit mol/L (= mol/dm) is used. The number concentration formula_9 is defined as the number of entities of a constituent formula_10 in a mixture divided by the volume of the mixture formula_3: The SI unit is 1/m. The volume concentration formula_13 (not to be confused with volume fraction) is defined as the volume of a constituent formula_14 divided by the volume"